聚乳酸薄膜处理对黄花菜保鲜效果分析

聚乳酸(PLA)是一种完全生物降解材料,为研究PLA薄膜对黄花菜的保鲜效果,以聚乙烯(PE)薄膜为对照,用不同厚度PLA薄膜对黄花菜进行了气调保鲜处理,在(25±1)℃贮藏期间对黄花菜的相关品质指标进行了测定。结果表明,PLA薄膜O_2和CO_2透过率低于PE薄膜,贮藏期间形成低氧高二氧化碳气体环境,抑制黄花菜呼吸作用,可明显减缓可溶性蛋白质、可溶性糖、叶绿素和抗坏血酸(Vc)含量的下降,抑制细胞膜渗透率、过氧化物酶(POD)活性的上升,延长黄花菜的贮藏保鲜期至10 d,而PE薄膜仅能贮藏6 d,厚度25μm的PLA薄膜保鲜效果最好。     

不同薄膜包装对黄花菜贮藏品质的影响

为探讨不同薄膜包装对黄花菜保鲜效果的影响，以黄花菜为试验材料，在0～2℃贮藏条件下，研究了5种薄膜[5．40μm聚乙烯袋（P1处理）、12．75μm聚乙烯袋（P2处理）、15．55μm聚乙烯袋（P3处理）、32．70μm聚乙烯袋（ P4处理）、5．40μm带孔聚乙烯袋（ CK）]对黄花菜贮藏效果的影响。研究结果表明，P4处理可在包装袋微环境中形成高浓度CO2（10．23％～11．73％）和低浓度O2（0．19％～2．53％），显著延缓采后黄花菜叶绿素的降解以及pH值的下降，从而明显抑制黄花菜的腐烂进程，并明显延长其贮藏保鲜期。综合比较可知，P4处理可以显著降低采后黄花菜品质的下降，延长其保鲜期。     

硫处理黄花菜中SO2残留量的变化

为了明确硫处理黄花菜的食用安全性,将硫处理的黄花菜在常温下贮藏,对贮藏后的黄花菜进行复水和加热熟化处理,测定贮藏、复水和加热熟化过程中黄花菜SO2残留量的变化。结果表明,不同质量浓度Na2S2O5溶液浸泡处理的黄花菜,在常温下贮藏90 d后SO2残留量降至100 mg/kg以下,复水60 min后SO2残留量降至32.3~50.6 mg/kg,再经加热熟化后,SO2残留量降至20.80~40.00 mg/kg;0.5 g/kg硫磺熏蒸处理的黄花菜中SO2残留量低于200 mg/kg,复水60 min后SO2残留量降至114~187 mg/kg;而撒拌Na2S2O5粉剂处理的黄花菜在常温下贮藏150 d后,再经120 min复水后SO2残留量仍高于200 mg/kg。说明Na2S2O5溶液浸泡处理质量浓度低于10g/L和硫磺熏蒸用量低于0.5 g/kg的黄花菜,SO2残留量符合国家标准,具有食用安全性。     

采收成熟度对台湾青枣耐藏性及品质的影响

对不同采收成熟度的台湾青枣贮藏期间的营养品质和耐藏性进行比较。结果表明：在贮藏初始，成熟度高的台湾青枣的糖、蛋白质、维生素C含量均高于成熟度低的，但贮藏2～3d后，成熟度高的台湾青枣商业品质迅速下降；而成熟度低的台湾青枣在常温下可贮藏6d。     

黄花菜应用研究现状与产业化开发对策

综述丁黄花菜的营养、保健和药用价值，分析了黄花菜贮藏加工利用现状，提出了黄花菜产业化发展对策。     

NO和采收成熟度对冷藏水蜜桃品质的协同影响(英文)

研究了硝普钠(SNP)处理对不同成熟度‘随缘’桃果实采后品质及褐变水平、多酚氧化酶(PPO)、过氧化物酶(POD)和超氧化物歧化酶(SOD)活性的影响。结果表明,在30d的贮藏过程中,SNP处理可维持不同成熟度桃果实的硬度,但其对可溶性固形物的影响不显著。在贮藏10天和30天时,SNP处理可减缓低成熟度桃果实可滴定酸含量的下降,但在高成熟度中,SNP处理果实的可滴定酸含量较对照低。然而,高成熟度结合SNP处理可提高桃果实的SOD活性,降低PPO和POD活性,并抑制其褐变水平。因此,高成熟度结合SNP处理可作为维持水蜜桃果实品质的有效方法。     

芦笋种子条件与发芽关系的研究

作者对芦笋果实成熟度，采种株株龄及贮藏年限与种子千粒重、发芽的关系进行了研究，并测定了不同贮藏年限种子的活力。结果表明：果实成熟度越好，所采种子千粒重、发芽势、发芽率也越高；后熟可提高这３项指标；成熟度越差，后熟效果越好，需要后熟的天数也越长。采种株株龄对发芽势的影响比对发芽率大；贮藏年限与活力指数呈极显著负相关，其相关系数为－０．９７；α－淀粉酶活性随贮藏年限增加而降低。     

不同成熟度百香果的贮藏特性研究

【目的】研究成熟度对百香果采后贮藏特性的影响。【方法】设计3种处理(七至八成熟、九成熟至全熟、以上两种成熟度混合)用低密度聚乙烯(LDPE)保鲜袋包装后热封,在12 ℃、相对湿度70%条件下贮藏9 d,每隔3 d测定百香果相关品质。【结果】随着贮藏时间的增加,果实失重率呈上升趋势,但3种成熟度处理之间差异不显著。七至八成熟果实呼吸速率和乙烯释放量不断增加,九成熟至全熟和不同成熟度混合包装处理的果实在采后贮藏6 d出现呼吸高峰与乙烯高峰,呼吸速率和乙烯释放量呈先上升后下降趋势。与七至八成熟、九成熟至全熟包装处理的果实相比,不同成熟度混合包装的果实贮藏期间可溶性固形物含量为16.26%、硬度为6 337.78 g/cm~2、果皮明亮程度下降最慢,可溶性蛋白质、Vc含量先下降后上升至20.91、36.17 mg/100mL。【结论】不同成熟度混合包装的百香果耐藏性优于七至八成熟和九成熟至全熟处理。     

干燥器贮罐稻种发芽研究

用干燥器密闭贮藏历年稻种资源发芽试验，结果表明：籼，粳，糯稻种的发芽率，发芽热，发芽指数年度间存在明显差异，表现灿稻－糯稻－粳稻。探明与和皮颜色，蛋白质含量高低无明显相关关系。在本试验条件下，籼稻可保存２０年，粳稻９年，糯稻１０年以上。影响稻种活力的因素除与本身遗传因子，种了成熟度外，和种子含水量，温度，贮藏方式有密切关系，科学发芽提高贮藏稻种的发芽力。     

不同温度和成熟度对杏贮藏期腐烂率和品质的影响

【目的】不同采收成熟度在常温及冷藏处理下对杏果实品质、腐烂率的影响，为杏果实在常温贮藏、冷藏条件下适宜采收成熟度提供判断指标和科学依据。【方法】以小白杏、油光大白杏为试材，按“转黄率”将果实分别划分为3个成熟度Ⅰ、Ⅱ、Ⅲ,测定果实硬度、品质、腐烂率，分析相关性。【结果】同品种杏果实不同成熟度之间存在差异，特别是VC含量差异显著((P<0.05)。随着成熟度的增加，果实硬度降低、可滴定酸含量下降，腐烂率、果胶及纤维含量升高，其他指标存在小幅度变化。在腐烂率上，同一成熟度常温贮藏远高于冷藏，同品种成熟度Ⅲ>Ⅱ>Ⅰ;常温条件下小白杏成熟度Ⅱ、油光大白杏成熟度Ⅰ表现较优，冷藏条件下小白杏成熟度Ⅲ、油光大白杏成熟度Ⅲ表现较优。【结论】常温储运时适宜采收小白杏成熟度Ⅱ、油光大白杏成熟度Ⅰ果实，冷藏储运时适宜采收小白杏成熟度Ⅲ、油光大白杏成熟度Ⅲ的果实。     

Web2.0,以个人为中心的互联网时代的到来

本文介绍了Web2．0的知识和背景，对Web2．0出现的基础以及典型技术和应用作了阐述，同时对其作出了前景展望。     

盐胁迫对葡萄苗期多胺和激素代谢的影响

【目的】 研究盐胁迫条件下,葡萄叶片中多胺含量、多胺氧化酶、多胺合成酶活性以及激素的动态变化,研究不同盐胁迫强度对多胺类物质及激素代谢的影响。【方法】 采用盆栽基质培养模拟盐胁迫环境,设置4个NaCl处理梯度:0 (CK)、1、2和3 g/kg。多胺和激素含量的测定采用高效液相色谱法,多胺合成及分解酶活性的测定采用紫外分光光度计比色法。【结果】 盐胁迫处理后,葡萄叶片中多胺含量和脱落酸含量较对照而言显著增加,玉米素含量显著降低,随胁迫时间的延长,Put、Spm、Spd、ABA以及PAO、DAO、ADC、ODC、SAMDC活性均呈先上升后下降趋势,在10 d及10 d后达到峰值。ZT呈逐渐下降的趋势,并随胁迫强度增大而减小;进行显著性分析后,叶片中多胺含量与Put、Spm、Spd含量呈极显著正相关,DAO、ADC、ODC活性与Put含量呈显著正相关,PAO与SAMDC活性与Spm和Spd含量也呈极显著正相关。【结论】 3种多胺经酶的合成代谢后和激素共同缓解葡萄苗所遭受到的盐胁迫,期间主要发生作用的是多胺合成酶,盐胁迫下多胺与激素含量之间的变化关系也十分密切。     

市级综合气象信息分析与管理系统的设计与实现

以抚顺地区3个国家基本站50余年气象资料为依托,采用Microsoft Excel工作表实现由气候和农业气候2部分构成的气象与农业综合信息处理系统的基本思路、方法、内容、用途和使用情况。为了实现气候分析及应用的科学化、客观化、系统化、规范化、程序化及连续化的业务目标,按业务流程设计与实现的,包括资料处理、气候趋势模拟、气候预测、气候鉴定、季节性信息化处理、农作物产量预报、气候生产潜力分析等一系列内容在内的系统建设。关键是解决了大量的计算问题,建立了区域性通用模式。     

Multi-variable grey model (MGM (1,n,q)) based on genetic algorithm and its application in urban water consumption

Urban water consumption has some characteristics of grey because it is influenced by economy, population, standard of living and so on. The multi-variable grey model （MGM（1,n））, as the expansion and complement of GM（1,1） model, reveals the relationship between restriction and stimulation among variables, and the genetic algorithm has the whole optimal and parallel characteristics. In this paper, the parameter q of MGM（1,n） model was optimized, and a multi-variable grey model （MGM（1 ,n,q）） was built by using the genetic algorithm. The model was validated by examining the urban water consumption from 1990 to 2003 in Dalian City. The result indicated that the multi-variable grey model （MGM（1,n,q）） based on genetic algorithm was better than MGM（1,n） model, and the MGM（1,n） model was better than MGM（1,1） model.     

Molecular detection of virulence genes in Campylobacter species isolated from livestock production systems in South Africa

Campylobacter species are a major cause of foodborne bacterial infections in both developed and developing countries worldwide. Campylobacter jejuni is responsible for the majority of infections. This study was conducted to identify virulenceassociated genes in Campylobacter species isolated from livestock production systems in South Africa. A total of 250 fecal samples consisting of cattle(n=50), chickens(n=50), goats(n=50), sheep(n=50) and pigs(n=50) were randomly collected from livestock in Eastern Cape and KwaZulu-Natal provinces of South Africa between April and October 2018. The samples were analyzed for the presence of virulence genes in Campylobacter species using molecular PCR-based methods. It was found that 77 and 23% of Campylobacter jejuni and Campylobacter coli respectively were isolated from all the livestock samples. There were positive significant(P0.05) correlations amongst all the virulence genes that were investigated. Chisquare and Fisher's exact tests were implemented to test for the effect of livestock species on the presence or absence of virulence genes. The study demonstrated that most of livestock species can potentially cause zoonotic infections and food poisoning due to the high prevalence of Campylobacter. The high prevalence of virulence genes highlights the significance of Campylobacter in livestock production systems in South Africa. This requires the implementation of one-health approaches to reduce the impact of foodborne and zoonotic diseases for the welfare of human and animal health.     

红苕饲粮中添加铜和/或喹乙醇对猪生产性能及某些血液生化指标的影响

选体重约38公斤的长白(♂)×成华(♀)杂交猪20头,随机分为四组,饲予四种不同的饲粮,研究饲粮中添加铜和/或喹乙醇对猪生产性能和某些血液生化指标的影响。结果表明:基础组、加铜组、加喹乙醇组和两者同时加组全期日增重分别为674、761、796、678克,日采食量分别为2.50、2.65、2.74、2.40公斤,饲料利用率分别为3.73、3.49,3.44、3.54,添加铜和/或喹乙醇对试验第65天血清铜兰蛋白、尿素氨及屠宰率、背膘厚和眼肌面积无显著影响(p>0.05);添加铜使65天血清碱性碱酸酶活性极显著增高(p<0.01),添加喹乙醇有使之升高的趋势,两者同时添加时,碱性酸磷酶活性降低。     

不同施肥水平对木薯氮磷钾养分积累、分配及其产量的影响

 【目的】通过比较不同施肥水平下木薯氮磷钾养分积累、分配和产量的差异,探讨粤北坡岗地优质高产木薯氮磷钾养分的最佳用量。【方法】以木薯品种南美119为材料,采用“3414”方案,在粤北翁源进行大田试验。试验共设14个处理。【结果】施肥处理的氮素主要分配到地上部,不施肥处理的氮素则主要分配到根部;不同施肥处理的磷素均主要分配到地上部;不施肥处理和不施钾处理的钾素主要分配到根部,不施氮处理的钾素在根、冠间分配较均衡。在木薯不同生长阶段,植株氮磷钾含量均呈下降趋势,但施氮、磷、钾化学肥料处理植株氮磷钾含量的下降速度小于不施氮、磷、钾化学肥料的处理。处理N2P2K2的氮、磷、钾含量和积累量在各生育期均为最大,不施肥处理（N0P0K0）的氮、磷、钾含量和积累量在各生育期均为最小（P＜0.05）。产量最高的是N2P3K2处理,为22 694.06 kg·hm-2,其次是N2P2K2处理,为21 417.87 kg·hm-2。【结论】木薯产量、氮磷钾养分积累及其在根冠间的分配,对施肥水平高度敏感, 适当比例的氮磷钾肥配合施用既可以显著增加木薯植株的氮磷钾含量和积累量,又可以提高产量。在粤北坡岗地木薯生产中,氮素最重要,在氮素得到满足的条件下,磷素较钾素更重要。在本试验条件下,氮磷钾养分最佳用量为358.80 kgN·hm-2、89.10 kg P2O5·hm-2和187.50 kg K2O·hm-2。     

Current progress on genetic interactions of rice with rice blast and sheath blight fungi

Analysis of genetic interactions between rice and its pathogenic fungi Magnaporthe oryzae and Rhizoctonia solani should lead to a better understanding of molecular mechanisms of host resistance, and the improvement of strategies to manage rice blast and sheath blight diseases. Currently, dozens of rice resistance (R) genes against specific races of the blast fungus have been described. Among them, ten were molecularly characterized and some were widely used for breeding for genetic resistance. The Pi-ta gene was one of the best characterized rice R genes. Following the elucidation of its molecular structure, interaction, distribution, and evolution, user friendly DNA markers were developed from portions of the cloned genes to facilitate the incorporations of the Pi-ta mediated resistance into improved rice varieties using marker assisted selection (MAS). However, rice blast is still a major threat for stable rice production because of race change mutations occurring in rice fields, which often overcome added resistance based on single R genes, and these virulent races of M. oryzae pose a continued challenge for blast control. For sheath blight, progress has been made on the exploration of novel sources of resistance from wild rice relatives and indica rice cultivars. A major quantitative trait locus (QTL), named qSB9-2, was recently verified in several mapping populations with different phenotyping methods, including greenhouse methods. The ability to identify qSB9-2 using greenhouse methods should accelerate the efforts on the qSB9-2 fine mapping and positional cloning.     

Virus Location and Lymphocyte Apoptosis in Lymph Nodes of Piglets Infected with PCV-2

The present study has been performed to understand the location of the virus, type of apoptotic cells, and their relation to lymph nodes of piglets infected with porcine circovirus type Ⅱ （PCV-2）. Nine 32-day-old conventional piglets free of infection with PCV-2 were used, and distributed into three groups： control group （n = 3）, piglets inoculated with PCV-2 alone （PCV-2, n = 3）, and PCV-2 inoculated and KLH immunostimulated group （PCV-2 ＋ KLH, n = 3）. Superficial inguinal lymph nodes from all piglets were collected for histological examination after 32 days postinoculation, and immunohistochemistry for PCV-2 detection. Location of apoptotic cells was detected with TdT-mediated dUTP nick end labeling （TUNEL） and cell cycle, and the apoptotic rates were measured by flow cytometry. The characteristic histopathological lesions of the piglets in PCV-2 and PCV-2 ＋ KLH were lymphocyte depletions in the cortex and paracortex of the lymph nodes, epithelioid-like macrophage infiltration, and intracytoplasmic inclusion bodies presented in epithelioid-like macrophages. PCV-2 was mainly found in epithelioid-like macrophages by immunohistochemistry. In the lymph nodes, lymphocytes presented higher apoptotic rates in the cortex by TUNEL, special B-cell areas, and similar apoptotic cells were found in this compartment in the control. The apoptotic rates of the lymph nodes were 0.41, 3.34, and 4.88% in the control, PCV-2, and PCV-2 ＋ KLH groups by flow cytometry, respectively. The apoptotic rates of lymph nodes for PCV-2 and PCV-2 ＋ KLH piglets were significantly higher than those for the control group （P〈0.05 and P〈0.01）. The proliferation index （PI） was 0.17_＋0.01, 0.12_＋0.01 and 0.12_＋0.04 in the control, PCV-2, and PCV-2 ＋ KLH group, the PI of the control group was higher than that of the other groups, but without the statistical difference. PCV-2 can induce lymphocyte depletion in lymph nodes of piglets by blocking cell proliferation and promoting apoptosis. This is one o     

内脐蠕孢属、平脐蠕孢属和凸脐蠕孢属的研究

本文报道了平脐蠕孢属(Bipolaris)一个新种,一个新组合,5个新记录以及凸脐蠕孢属(Exserohilum)一个新记录。讨论了内脐蠕孢属(Drechslera)、平脐蠕孢属、凸脐蠕孢属与长蠕孢属(Helminthosporium)的关系,并就我国已报道的长蠕孢属真菌按Alcorn等~([1,3,4,5,24])人的意见,逐个进行了订正。